It was making a joke of Star Trek. If you ever watch Star Trek you'll notice that they can touch the same button and get two different things to happen. South Park does this kind of stuff a lot(the one where the kid gets eaten by the monster was actually a take off of a real Star Trek episode[he is even wearing a shirt with the Star Trek symbol thing]).

"Call me" MrKitty is right: Those redshirted Trek-xtras were always the most expendable Star Trek crew members; in fact, the only TV article of clothing more dangerous than the red shirts w/the insignia is a red parka ;)